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The Structure and Strength of Basal Ice in the Suess Glacier, Antarctica

Paul Sirota
Department of Geography, University of Otago, Dunedin, New Zealand

 
Abstract

Direct-shear tests were conducted on clean glacier ice, several types of basal ice and frozen substrate material from the basal zone of the Suess Glacier, Taylor Valley, Antarctica. Different strain-rates approximating three orders of magnitude were employed in order to examine whether the rheology of basal material changes with a change in the rate of strain. The results of testing indicated that the peak shear-strength of the materials decreased as slower strain-rates were applied. High debris-concentration, solid facies and frozen substrate attained the greatest values of shear-strength. The lowest values were found in amber ice, which contains a significant solute concentration and finely dispersed sediment particles. High solute concentration along with low sediment content within the ice lattice appears to decrease the shear-strength of basal ice. Results from this study indicate that preferential deformation is likely to occur in basal ice above the saturation point (> 25% ice) and that if frozen substrate and solid debris facies deform, it is likely to be at a much slower rate than basal ice.

 
Reference

Sirota, P. 1999. The Structure and Strength of Basal Ice in the Suess Glacier, Antarctica. Unpublished BSc (hons) dissertation, in Geography, at the University of Otago, Dunedin, New Zealand. 100 pp.

© 2009 Department of Geography, University of Otago, Dunedin, New Zealand